Means for regulating the blast in ore-roasting furnaces



(No Model.) 2 Sheets-Sheet 1.

R. PEARCE MEANS FOR REGULATING THE BLAST IN ORE RO ASTI-NG FURNACES. No. 506,129. PatentedO ot. 3; 18 93.

Q Q I a f Q g i s k a N z Ha 3g 0 w 1 u I v a Q N N Q m I m N "a Q I v {\3 a I! g f W a 6 s5 i w a 0 jg 'u 2 sneets shet 2.

R. PEARCE. MEANS FOR REGULATING THE BLAST IN ORE ROASTING FURNACES. Nof506 1Z9.

(No Model.

Patented Oct. 3,1893.

U ITED STATES PATENT OFFICE- RIC-HARD PEARCE, OF DENVER, COLORADO.

MEANS FOR REGULATING THE BLAST lN QRE-ROASTING FURNACES.

SPECIFICATION forming part of Letters Patent No. 506,129, dated October 3, 18 93.

Application filed Mm]. 29, 1893.

To all whom it may concern.-

Be it known that I, RICHARD PEARCE, a subect of the Queen of Great Britain, residing at Denver, in the county of Arapahoe and State of Colorado, have invented a certain new and useful Improvement in Means for Regulating the Blast in Ore-Roasting Furnaces, of which the following is a full, clear, and exact description.

In operating smelting or ore roasting furnaces constructed in accordance, for example, with the principle embodied in my Patent N 0. 488,797, dated December 27, 1892, it is desirable, even when not necessary, to be able to control the quantity Or volume of air admitted as the roasting operation proceeds. For instance, the freshly admitted ore must be carried some distance into or around the furnace before it becomes sufficiently hot to be benefited by'the oxidizing action of the air blast, and the farther the ore travels the hotter 1t becomes and the greater avidity it has for the air, and hence the best results will be obtained by regulating the admission of air according to the receptivity of the charge for 1t. Moreover, by so regulating the admission of the air, the loss of fine particles of ore is greatly reduced.

Now, my invention consists in means for regulating the volume of air admitted to a charge of roasting ore in accordance with the condition of the ore to combine with it; as I w1ll proceed now more particularly to set forth and claim.

In the accompanying drawings illustrating my invention in the several figures of which like parts are similarly designated, Figure 1 1s a partly sectional plan View of a portion of a furnace constructed in accordance with my patent above referred to and supplied with the elements of the apparatus of the present mvention. Fig. 2 is a vertical cross-section thereof. Fig. 3 is a cross-section of one of the stirrer arms and blast pipes. Fig. 4 is a side view thereof broken away opposite the air valve, and Fig. dis a plan view of the parts shown in Figs. 8 and 4.

The furnace herein selected to illustrate this invention being like that shown in said patent, may be similarly described in connecse'rial No. 468,196. (No model.)

tion with the same reference characters, as follows:-

The furnace is composed of an outer annular wall a, built up of red brick or othersuitable material, and a corresponding inner concentric wall I), of like material; and between these walls there is a filling c of suitable material upon which is laid the hearth cl, and this hearth is composed of fire brick or other refractory substance.

6 is the arch or crown of the furnace, sprung from skew-backs a and b on the outer and inner walls respectively. The outer wall is provided with wrought iron or other bands (2. and a, to resist the thrust, respectively, of the hearth and arch. The inner wall b is made with a continuous slot or opening f just above the hearth; and the lower edge of this slot is protected by angle-irons g, while the upper edge, constituted of the skew-backs is suspended, upon angle-irons h, which in turn are suspended by U-bolts 'i, which are supported by I-beams j, and these *I-beams rest at their outer ends, upon shoes is mounted upon the'outer wall a, and are supported at their inner ends upon brackets Z, which are mounted upon a central hollow column m. Obviously, the I-beams j may be arranged otherwise than as just described, and as shown in the drawings, in order to accomplish the purposes for which they are intended, but as shown, the said I-beams not only serve to support the skew backs of the inner Wall but they also serve to stay the hollow column m from which, as shown, they radiate.

p is the charging opening, a part only of which is shown, and at point q is the outlet.

0 is the passage in the crown of the fur- 111cc leading to the dust chamber and stack (not shown, but as in said patent) for conveying away the gases and other products of combustion, and (1 g arethe opposite walls of the mouth of the furnace.

The stirrers are composed of hollow arms 8, which radiate from a common hub 3 which encircles thehollow column m. The outer ends 8 of these arms are made detachable from the inner ends'and are connected therewith by couplings s which couplings are arranged outside the inner wall b. The ends 8 of the arms are provided with rabbles t rigidly suspended therefrom, at about an angle of eighty degrees with the axes of said arms, and a sufficient number of these rabbles is attached to each arm to extend practically across the width of the hearth. The hub s is made hollow and opposite the said hub the hollow column m is provided with openings m In connection with the said hollow column is an air forcing apparatus (not shown) by which air may be supplied to the said column. The sections .9 of

the arms are provided with outlets for the air,

and by preference these outlets are made as tubes 7.6, which extend downwardly behind the rabbles so as to supply air to them, whence it escapesinto the furnace and serves for oxidizing purposes in the process of calcination. In order to close the space between the hollow column and the hollowhub .9 any suitable flexible covering 1) may be employed, and fastened down in any suitable manner to make practically air tight joints. See for example, the patent referred to. w is the slot closing shield as in the patent.

The circular track y is supported in any suitable manner, as upon girders y borne by the inner wall and the hollow column. The couplings s are provided with wheels or rollers y which move upon said track and support the arms upon such track. The arms are provided with a suspended toothed ring .2 and this ring is guided and braced-on the inside by guide rollers e which may be mounted upon the supports 1 of the track y. A pinion 2 is mounted upon a shaft 3 and engages the toothed ring 2, and this shaft 3 is connected by gearing 4 with the power shaft 5. Obviously, by the rotation of the pinion 2, the arms .5 will be rotated about the column m, and the rabbles will be caused to traverse the hearth in its entire circumference, taking in their course the ore from the inlet and progressively moving it and continuously stirring it from that point to the point of discharge.

The stirrer arms .9 are supplied with the means for effecting the purposes of the present invention as follows: A valve 12, which may be a fiat disk of metal, like a stove-pipe damper, is inserted in each stirrer arm and supported to turn therein on a spindle 13 which projects up out of the stirrer arm and is provided with a two-armed lever 14 and is acted upon, to hold it in given position, bya spring 15 fixed to the stirrer arm. At appropriatepoints on the inner wall are arranged brackets 16 and 17 of different length, having respectively the depending fingers 18 and 19 to act upon one or the other of the limbs of the levers 14 as the stirrer arms are moved around.

The operation is as follows :-The valve is opened or closed to the blast coming through the hollow stirrer arm from the hollow column as said valve stands respectively parallel or at right angles to the axis of the stirrer arm. The valve is brought into these positions successively as the stirrer arms are carried around, by the action of one or the other of the fingers 18 or 19 on the limbs of the lever 14. This successive opening and closing of the valve either wholly or in part may be repeated more often by using a properly shaped lever 14 and increasing the number of operating fingers. As already observed, the spring 15 holds the valve in whatever position it may be given. Or the valve may be opened and closed more or less completely by degrees by using an appropriately shaped lever 14 and a suitable number of fingers. As the series of stirrer arms are swept around the furnace in the direction of the arrow Fig. 1, and the stirrer arm 20 comes next the ore-charging 'inlet, the pin 19 will strike one end of the lever 14 and close the valve and shut off the air from the fresh charge, and then as this same arm passes the finger 18 said finger will strike the other limb of the lever 14 and open or partly open the valve and admit air to the heated ore. If the valve be opened only partly, it maybe opened fully by a finger arranged farther on in the line of travel of the stirrer arm.

Practically, the ore when roasting hasto travel about a fifth of the circle of the furnace before it becomes sufficiently hot to be benefitted by the oxidizing action of the blast of air, and hence by shutting 05 the air during the passage of the rabbles through this space, the temperature of this part of the furnace is less variable, and the risk of loss of fine particles of ore by the action of the blast is greatly reduced and the ore itselfis prepared to receive and utilize theair.

What I claim is" 1. In an ore roastingfurnace, the combination of a hearth or furnace proper, an inlet and an outlet for the ore, devices to move the ore through the furnace from the inlet to the outlet, means to supply air to the ore in the furnace, and means constructed and arranged to be actuated by the ore-moving devices to throw off and on the supply of air as the ore is moved from the inlet to the outlet, substantially as described.

2. The combination in an ore-roasting furnace of a hearth or furnace proper, hollow stirrer-arms having rabbles extending into the furnace, means to rotate said stirrer-arms and thereby cause their rabbles to move through such furnace, valves in such stirrer arms and means to operate such valves as the stirrer arms progress through or around the furnace, to cut off the air until the charge is heated sufficiently to combine therewith and then to admit the air, substantially as described.

3. The combination in an ore-roasting furnace of a hearth or furnace proper, hollow stirrer arms having rabbles extending into the furnace, means to rotate said stirrer-arms and thereby cause their rabbles to move bine therewith and then to admit the air, subthrough such furnace, valves in such stirrer stantially as described. to arms, and a series of fingers arranged at intervals upon the furnace in the line of travel of the valves and adapted to engage such valves as the stirrer arms progress through or around the furnace, to cut ofi theair until the charge is heated sufficiently to com- In testimony whereof I have hereunto set my hand this 24th day of March, A. D. 1893.

RICHARD PEARCE. Witnesses:

FRANK REYNOLDS, JESSE D. HALE. 

